Synthetic detergent bar compositions



assasss 1 SYNTHETIC DETERGENT nan cor irosrTroNs Application December 12, 1956 Serial No. 627,960

6 Claims. (Cl. 252-452) (Granted under Title 35, U. S. Code (1952), sec. 265} No Drawing.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This application is a continuation-in-part of application S. N. 578,850, filed April 17, 1956, and relates to improved synthetic detergent bar compositions comprising a mixture of sodium or potassium salts of OL-SllifO- nated, long straight chain saturated acids and corresponding ammonium or substituted ammonium salts.

Heretofore, synthetic detergent bars have suffered from several defects. They may be expensive to manufacture and not susceptible to manufacture in conventional soap bar equipment. They may be sticky or tacky, with objectionable de-fatting action on the human skin. They may lack desirable lathering characteristics, and not be very effective in hard Water. They may be too water soluble and waste away rapidly in use, or contain large amounts of inert non-detergent filler added in an attempt to minimize other defects.

An object of our invention is to provide synthetic detergent compositions which may be readily processed into bars in conventional soap bar forming equipment. A particular object is to provide synthetic detergent compositions which have sufiicient body and firmness so that the addition of inert, non-detergent filler is unnecessary in the manufacture of the detergent bars. Another object is to provide synthetic detergent bars having in use a favorable neutral reaction or a mildly acid reaction similar to the pH of the human skin. A further object is to provide synthetic detergent bars which are effective in hard water, have good lathering properties, and do not form undesirable curds, scums, films or deposits. Other objects of the invention will be apparent in further description.

Sodium or potassium salts of ot-sulfonated long chain saturated acids such as sodium a-sulfopahnitic acid,

13CH or dipotassium a-sulfostearate,

CH (CH CH(SO K)CO K are recognized to have detergent properties but have not found wide general use as detergents because of certain deficiencies, including limited solubility in water at room temperature, inadequate foaming properties, and inferior detergency at low concentrations.

We have discovered that improved synthetic detergent bars can be made from certain combinations of sodium or potassium salts of u-sulfonated long straight chain' saturated fatty acids with corresponding amonium or substituted ammonium salts. This discovery is unexpected in view of the cited deficiencies of the sodium and potassium salts as detergents.

The discovery is furthermore unexpected since we have Patented Jan. 6, 1959 found it impossible to prepare a satisfactory synthetic detergent bar from the sodium and potassium salts as the only active detergent. The bars formed were hard, brittle, and chalky, were only water soluble to a slight extent, and had poor cleansing properties. It was likewise impossible to prepare satisfactory synthetic detergent bars from the ammonium or substituted ammonium salts of oc-SlllfOIlfltCd fatty acids as the only active detergent. Bars formed from only the ammonium salt were hard and brittle. Bars formed from only the triethanolammonium salt were soft and sticky, and too readily soluble and wasteful in use, with a thin non-persistent lather.

The sodium or potassium salts of a-sulfonated saturated long chain fatty acids of the synthetic detergent bar composition of our invention have the general Formula I H SOaM (Formula'I) where R is a long straight chain alkyl group of 14 to 22 carbon atoms, preferably C H or C H M is Na or K and M is Na, K or H.

The ammonium or substituted ammonium salts of asulfonated straight chain saturated fatty acids of the improved synthetic detergent bar compositions of our invention have the general Formulas II or III:

liI $03M R-O\ (Formula II) COzH (Formula III) In Formulas II and III, R is a long straight chain alkyl group of 14 to 22 carbon atoms, preferably C H or C H M is Na or K, and M" is an amonium or substituted ammonium radical, preferably NH, or

Exclusive of small amounts of water, lanolin, perfume, whitening or coloring matter or the like, the improved synthetic detergent bar composition of our invention may comprise from 4090% by weight of the sodium or potassium salts of Formula I with 10-60% by weight of the ammonium or substituted ammonium salts of Formulas II and III. The ratios of the different salts and the degree of neutralization of the carboxyl group are readily controllable to produce an improved synthetic detergent bar with a neutral or a mildly acid reaction in use, similar to the pH of the human skin. To some extent the adequately soluble acid magnesium salt, magnesium u-sulfopalmitic acid,

can be used to supplement the lathering properties of the ammonium or substituted ammonium salts.

In a preferred embodiment of our invention the mono:

sodium salts of a-sulfonated hydrogenated tallow acids.

(Formula I, M=Na, M'=I-I) are intimately mixed with aqueous ammonia to give an improved synthetic detergent bar composition,.43% by'weight on the dry: basis with respect to the monosodium salts of a-sulfonated hydrogenated tallow acids (Formula I), and 57% by weight with respect to the sodium ammonium salt (Formula II, M=Na, M==NH Expressed in another manner this improved synthetic detergent bar composition on the dry basis has the mole ratio .44 monosodium salt: 56 sodium ammonium salt, and the gram'equivalent proportion 50 sodium: 28 ammonium: 22 carboxylic hydrogen.

In another preferred embodiment of .our invention the monosodium salts of a-sulfonated hydrogenated tallow acids (Formula I, M=Na, M'=H) are intimately mixed with triethanolamine in the presence of about -l5% of water and the improved synthetic detergent bar composition on the dry basis is 67% with'respect to the monosodium salt (Formula I) and 33% with respect to the sodium triethanolammonium salt (Formula II, M=Na, M"=NH(C H OH) manner the composition has the mole ratio 74 monosodium salt: 26 sodium triethanolammonium salt, and the gram equivalent proportion 50 sodium: 13 triethanolammonium: 37 carboxylic hydrogen.

In still another preferred embodiment of our invention the improved synthetic detergent bar composition is an intimate mixture consisting on the dry basis of 75% by weight of the disodium salts of a-sulfonated hydrogenated tallow acids (Formula I, M=M=Na) and by Weight of the mono triethanolammonium salt (Formula III, M"=NH(C H OH) Expressedin another manner the composition has the mole ratio 79 disodium salt: 21 mono triethanolammonium salt and the gram equivalent proportion 79.2 sodium: 10.4 triethanolammonium: 10.4 carboxylic hydrogen.

Complete neutralization of all carboxylic hydrogen in the improved synthetic detergent bar compositions of our invention is to be avoided. The presence of carboxylic hydrogen as in Formulas I or III may provide a bene- Expressed in another ficial neutral or mildly acid reaction in use of the detergent bar. The presence of carboxylic hydrogen as in Formulas I or III is believed also to contribute to controlled plasticity in forming the detergent bar.

The improved synthetic detergent bar compositions of our invention are sufiiciently plastic to be readily processed into attractive bars in conventional soap bar forming equipment, and are also easily handled in smaller scale plodding, milling andpressing operations in the laboratory, as well. The bars so formed are free from the defects usually attributed to synthetic detergent bars. They are not sticky or tacky, and have no objectionable de-fatting action on the human skin. They are very etfective in hardwater, have controlled solubility, have excellent lathering characteristics, and are especially efiicient in difiicult cleaning operations, removing grease and grime and the like without the necessity of an incorporated harsh abrasive. They do not Waste away-rapidly in use through excessive solubilityiand do not containnon-detergent filler. Through their neutral or midly acid reaction in use they may be beneficial to the hands, without excessive removal of the protective acid mantle onthe human skin.

The required salts of the a-sulfonated long chain saturated fatty acids can be readily manufactured in an in-f' expensive process. The a-sulfonated long chain saturated" fatty acids obtained from the reaction of sulfur trioxide or chlorosulfonic acid with the saturated fatty acids can be isolated, if desired, in good yield. The isolated a-Sillfonated acids can then be readily converted to the desired salts which are then intimately mixed to form the improved synthetic detergent bar composition.

Isolation of the a-sulfonated fatty acid is, however, not v required. The desired salts can be formed directly fromi TABLE 1 Improved synthetic detergent bar compositions V [Ratios of Two Types of Salts (Na or K Type: N114 or Substituted NH; Type) Gram equivalent proportions Ammonium or substituted Weight Mole H No. Sodium or potassium type ammonium type ratio ratio of salts of salts N a or NH; or H from K NH(0;H OH)3 CODE;

1 Monosodium salts of a-sulfonated hydrogenated tallow RCHSOBN3* 43:57 44:56 28 22 acids, average molecular weight 375.

CO2NH ROHSOrNa O H Average molecular weight 392 p 2 2 do RCHSOaNa' 67:33 74:26 50 13 37 r OOzNH(CzH4OH)a Average molecularweight 524 v 3 Potassium a-suliostearic acid Q. Cifl 33CHSO3N9-** 67:33 74:26 50 13 37 OOQNH(C2H4OH)3 4 Potassium a-sulfostearic acid CwHuCH S 03K 71:29 77:23 50 12 38' 2NH(Cz 4 )a 5 Disodium salts oi a-sulionated hydrogenated tallow acids, 'Iriethanolammoniuul a- :30 74:26 74 i3 '13 average molecular weight 397. sulfopalmitic acid.

RGHSO Ns.

CO1N8 p 6 do Mono-hiethauolamine salts 75:25 79:21 79.2 10. 4 10. 4

of a-sulfonated hydrogenated tallow acids. ao'nsommomioma 00311 a Average molecular weight 502 7 (1n Aminlonium a-sulfopalmitic :10 89:11 89 5.5 5.6

3.81 i 3 fln Triethanolammonium a 90:10 92:8 92 4 4'- sulfostearic acid. v 9 Sodium a-suliostearic ri do 90:10 92:8 46 4 50 during the bar forming Formed by the reaction of aqueous ammonia or triethanolamine with excess of the monosodium salt of a-sulionated hydrogenated tallow acids,

process.

Formed by the reaction of aqueous triethanoiamiue excess of sodium or potassium a-sulfostearic acid, during the bartorming process.

the sulfonation reaction mixture by neutralization of the sulfonic acid group by selected ratios of sodium or potassium hydroxides and ammonium or substituted ammonium hydroxide, with either no neutralization of the carboxyl group, or incomplete neutralization of the carboxyl group, in accordance with the desired composition. Alternatively, the synthetic detergent bar composition is advantageously made 'by first isolating the monosodium or 'monopotassium salt (Formula I, M'=H-) by adding aqueous sodium chloride or potassium chloride to the sulfonation reaction mixture. The monosodium or monopotassium salt, by mixing with a calculated amount of aqueous ammonia, aqueous triethanolamine, or other aqueous nitrogenous base, is partially transformed to a mixed salt (Formula 11) without complete neutralization of the carboxyl group. The intimate mixing and partial transformation to the mixed salt is advantageously accomplished in crutching, milling or plodding or similar steps in the course of formation of the improved synthetic detergent bar.

The fatty acids which are a-sulfonated with sulfur trioxide or chlorosulfonic acid may be individual fatty acids such as palmitic or stearic acid, or may be commercial saturated fatty acids with a high content of palmitic and stearic acid and a. low iodine value. The saturated acids of tallow or the fatty acids of hydrogenated tallow are eminently suitable.

Table I illustrates, but is not restrictive of, the improved synthetic detergent bar compositions of our invention. The figures given are on the dry basis, exclusive of water, small amounts of whitening or coloring agent, lanolin, perfume, and the like. The water content is preferably in the range of 9 to 16%, usually about 12%, of the weight of the finished bar, but the actual value is not considered critical. The addition of a small amount of solubilized lanolin, shown in Example 1 to be readily feasible, is not considered a significant factor in the process.

The improved synthetic detergent bar compositions of our invention are further illustrated in the following examples:

EXAMPLE 1 A mixture of 1050 grams of the disodium salts of a-sulfonated hydrogenated tallow acids (RCH (SO Na) CO Na average molecular weight 397), 350 grams of the corresponding acid triethanolammonium salts (RCH(SO NH(C H OH) )CO H average molecular weight 502), 15 grams of solubilized lanolin and 160 ml. of water was processed in a small scale plodder. The extruded plastic strands were easily stamped into firm, smooth bars which had excellent cleansing and lathering properties in soft or hard water.

The composition corresponds to No. 6 of Table I.

EXAMPLE 2 Eight milliliters of 17.5% aqueous ammonia were added to 50 grams of the monosodium salts of u-sulfonated hydrogen tallow acids (RCH(SO Na)CO I-I) while being processed on a two-roll mill. The homogeneous product was readily pressed into firm smooth bars. Hand Washing tests showed excellent foaming and cleansing properties. The composition corresponds to No. 1 of Table I.

EXAMPLE 3 Triethanolamine was added as 6.6 grams of a 47% aqueous solution to 30 grams of the monosodium salts of a-sulfonated hydrogenated tallow acids (RCH(SO Na)CO H) during the milling process on a two-roll mill. The homogeneous product was easily pressed to a firm smooth bar which exhibited good foaming and cleansing properties. The composition corresponds to No. 2 of Table I.

EXAMPLE 4 A mixture of 45 grams of sodium wsulfostearic acid, 5 grams of triethanolammonium a-sulfostearic acid and 6 ml. of water milled on a two-roll mill was easily pressed to a firm smooth bar which exhibited good cleansing and lathering properties. The, composition corresponds to No. 9 of Table I.

EXAMPLE 5' A mixture of 40 grams of sodium u-sulfostearic acid, 5 grams of magnesium u-sulfopalmitic acid 5 grams of triethanolamine and 6 ml. of water was milled on a two-roll mill and pressed into firm smooth bars which had good foaming and cleansing properties. On a dry basis the composition has the weight proportion 54 sodium a-sulfostearic acid: 36 sodium triethanolammonium a-sulfostearate: l0 magnesium ot-sulfopalmitic acid, the corresponding mole proportions 60:28:12 and the gram equivalent proportion 45 sodium: 15 triethanolammonium: 3 magnesium: 37 carboxylic hydrogen.

We claim:

1. A synthetic detergent bar consisting essentially of, on the active dry detergent basis, from 4090% by weight of salts of alpha-sulfonated fatty acids of the general formula,

Y H $03M.

and 10-60% by weight of salts of alpha-sulfonated fatty acids selected from the group consisting of where R is a straight chain alkyl group of from 14-22 carbon atoms, M is selected from the group consisting of sodium and potassium, M is selected from the group consisting of sodium, potassium, and hydrogen, and M" is selected from the group consisting of ammonium and triethanolammonium, the amount of carboxylic hydrogen in said salts always constituting from about 4% to about 50% of the total gram equivalents of sodium, potassium, ammonium, triethanolammonium, and carboxylic hydrogen.

2. A synthetic detergent bar composition as in claim 1 in which the proportionsof sodium and potassium are from 46 to 92 gram atoms, the proportions of ammonium and triethanolammonium are from 4-28 gram equivalents, and the proportions of carboxylic hydrogen are from 4-50 gram atoms, the sum of the three in every wherein M is selected from the group consisting of -'NH; and NH(C H OH) and R is a straight chain alkyl group of from 1422 carbon atoms. a

4. A synthetic detergent bar composition consisting essentially of, on the dry active detergent basis, from 60 to 90% by weight of a salt of an a-sulfonated fatty acid selected from the group consisting of OOzNa and 1;! 803K R-C COzK and from 10 to 40% by weight of a salt of an a-sulfonated fatty acid selected from the group consisting of H SO3NH4 CO H and v H SsNH( G2H H)a COIH where R is a straight chain alkyl group of from 14-22 carbon atoms.

5. A synthetic detergent bar composition consisting essentially'of, on the dry active detergent 'ba sis' from .40-% by weight of a salt of-an u-sulfonated fatty 'acid of theformular r H $03M 7 I/ R- C C0211 and from 20-60% by weight of a salft of an a-sulfonated fatty acid of the formula 1'1 s03M R-C V 0 02M 7 Where R is a straight chain 22 carbon atoms, M is selected from the group consisting of sodium and potassium, and M is selected from the group consisting of --'-NH and -NH(C H OH) 6. A synthetic-detergent bar composition as in claim 1 where R is the straight chain alkyl radical selected from the group consisting of I and mixtures of CH (CH and CH (CH derived from a member selected from the group consisting of commercial stearic acid, the saturated acids of tallow, and hydrogenated tallow fatty acids.

I References Cited inthe file of this patent UNITED STATES PATENTS 2,195,186 Mayer Mar. 26, 1940 alkyl group of from l4 to' Bodman Sept. 17,1946- 

1. A SYNTHETIC DETERGENT BAR CONSISTING ESSENTIALLY OF, ON THE ACTIVE DRY DETERGENT BASIS, FROM 40-90% BY WEIGHT OF SALTS OF ALPHA-SULFONATED FATTY ACIDS OF THE GENERAL FORMULA, 